1. Field of the Invention
The present invention relates to an information processing apparatus, an information processing system, an information recording medium, an information processing method, and a program. More specifically, the present invention relates to an information processing apparatus, an information processing system, an information recording medium, an information processing method, and a program, with which sub-content or the like corresponding to content stored on an information recording medium such as a Blu-ray Disc® or a DVD is downloaded from a server and stored onto a local storage section, thereby performing a content usage process that uses content stored on the disc and content (subsequent data) stored on the local storage section.
2. Description of the Related Art
Various kinds of software data, including audio data such as music, image data such as movies, game programs, and various application programs (hereinafter, these will be referred to as content) can be stored on a recording medium, for example, an information recording medium such as a Blu-ray Disc® or a DVD (Digital Versatile Disc), and then provided to the user. A Blu-ray Disc® using blue laser is a disc capable of high-density recording and can record a large volume of video content or the like as high-definition data, and its use has been increasing recently.
A content-storing disc can be mounted in various kinds of apparatus, for example, a playback apparatus such as a disc player owned by a user, or a PC (Personal Computer), for playback of content.
Distribution rights or the like for many kinds of content such as music data and image data are typically owned by their creators or sellers. Therefore, offering of such content to a user is typically subject to a certain usage restriction, that is, only an authorized user is permitted to use the content. For example, control is performed so as to prevent indiscriminate copying of content without permission or the like.
Examples of content usage control adopted for a Blu-ray Disc® include dividing content into units (CPS units) and performing encryption on a unit-by-unit basis, or performing management in association with usage control information (Usage Rule). Content is divided into CPS units, and use of each CPS unit is permitted within a range defined by the usage control information (Usage Rule) corresponding to the unit.
In many cases, usage control information (Usage Rule) is recorded onto a disc together with content. At the time of content playback, a playback apparatus reads, from the disc, usage control information corresponding to the CPS unit to which the playback content belongs, and performs content playback in accordance with the usage control information. Usage control information (Usage Rule) is information recording, for example, content copy/playback control information (CCI), more specifically, information regarding permitted forms of usage and unpermitted forms of usage, such as whether copying of the content in question is permitted or not permitted.
If content belonging to a CPS unit is encrypted content, a CPS unit key as an encryption key corresponding to the unit is associated with the unit. At playback of the encrypted content, a decryption process using the CPU unit key is performed. A CPS unit file storing a CPS unit key is also recorded on a disc. In this way, usage of content stored on a Blu-ray Disc® is controlled under strict usage management.
Further, the Blu-ray Disc® standard also defines usage control in a case where supplementary data corresponding to content recorded on a disc, for example, subtitle data or dubbed data corresponding to movie content, service data corresponding to other kinds of content, or content such as a moving image or still image is downloaded as subsequent data (also called “trailer”) from a server for use.
It should be noted that a content usage system that acquires subsequent data (trailer) from a server or the like, records the subsequent data onto a local storage section such as a hard disk, and plays back the subsequent data together with disc-recorded content is disclosed in, for example, Japanese Patent No. 3959725 and Japanese Unexamined Patent Application Publication No. 2003-140662.
AACS (Advanced Access Content System) exists as a standard for content usage control for a Blu-ray Disc®. This standard defines usage control of not only content that has been recorded on a disc but also of subsequent data stored on the local storage section as mentioned above.
When content recorded on a disc such as a Blu-ray Disc®, and subsequent data recorded on a local storage section such as a hard disk are to be played back together on a user apparatus, the playback process is performed by building a virtual file system (VFS) that combines the disc-stored content and the content stored on the local storage section such as a hard disk. Through this VFS-based playback process, playback can be performed in the same manner as if from a single medium.
At the time of this VFS building process, file names of subsequent data stored on the local storage section are converted into file names for VFS settings. When setting these subsequent-data files on the VFS, it is necessary to set the file names for VFS in such a way that the file names do not overlap on the VFS and allow reliable file identification.
That is, it is necessary to convert [File Name on Local Storage Section] into [File Name on VFS]. For this file name conversion process, the user apparatus holds a file name conversion table. This file name conversion table is called a manifest file (BUMF: Binding Unit Manifest File).
To perform playback on the user's information processing apparatus by using both content stored on a disc and content stored on a local storage section, it is necessary to build a virtual file system (VFS) by using a manifest file (BUMF: Binding Unit Manifest File) serving as a file name conversion table.
It is not necessarily the case that subsequent data (trailer) to be provided to the user apparatus from the server has been determined at the time of manufacture of a disc. It is often the case that subsequent data is created and provided to the user after the user's purchase of the disc. Also, in some cases, new subsequent data is sequentially created. That is, in some cases, new subsequent data is sequentially provided to the user with the elapse of time after the release of the disc in the sequence of
first subsequent data,
second subsequent data,
third subsequent data,
and so on.
Subsequent data to be provided to the user is not limited to content files storing content substance data such as an AV stream but in some cases also includes updated content files, usage control information files, CPS unit key files, and the like corresponding to disc-stored content. Further, usage control information files, CPS unit key files, and the like corresponding to the subsequent data are also included.
When the user apparatus has acquired subsequent data from the server, it is necessary to build an updated virtual file system (VFS) allowing use of the acquired subsequent-data files. When updating of the virtual file system (VFS) is incomplete, for example, when content files have been received as subsequent data but CPS unit key files corresponding to the content files have not been received, updating of the virtual file system (VFS) is incomplete. In such a case, the user apparatus is not able to perform content playback.
Therefore, it is necessary that the file set of subsequent data received from the server be a file set that allows complete updating of the virtual file system (VFS).
As described above, after provision of a disc to the user, subsequent data is provided from the server at various timings, for example, in the sequence of the first subsequent data, the second subsequent data, the third subsequent data, and so on. The file set included in the subsequent data at these timings varies in settings.
As a program for making access to the server from an information processing apparatus on the user side to execute acquisition of subsequent data, a program stored on a disc together with content is used in many cases. For example, a BD-J program, which is a Java® program set in correspondence to a Blu-ray Disc®, is recorded on the disc together with content. The user's information processing apparatus reads this program from the disc and executes the program.
Access and subsequent-data acquisition request to the server are executed in accordance with the descriptions of this program. Therefore, it is necessary that the program (BD-J program) be pre-recorded with information for acquiring files necessary for a complete update of the virtual file system (VFS).
However, in the actual process, creation of subsequent data is often performed after a disc on which a program (BD-J program) and content are recorded is provided to the user. Therefore, it is difficult to clearly determine a file set included in subsequent data, that is, a file set necessary for a complete update of the virtual file system (VFS), at the stage of program (BD-J program) creation which is executed before manufacture of the disc.